The present invention relates to a method for connecting the end of a new fiber band to the end of a fiber band running into an open-end spinning arrangement. The end of the running fiber band is drawn off by a feeding device of the spinning arrangement and the new fiber band is drawn from a container and threaded into the spinning arrangement. The feeding device is brought to a standstill whereupon the end of the new fiber band is attached followed by an automatic start spinning of the spinning device.
In a method of the above-mentioned kind as disclosed in German application DE-OS No. 25 18 224, it is provided that the presence or absence of a running fiber band is determined by means of a touch sensor which is arranged at least one staple length in front of the inlet of the fiber band into an opening device. The intention here is to prevent a yarn number from being spun which differs from the rest of the yarn after the fiber band has been used up. The end of the new fiber band is then connected by hand whereupon an automatic start spinning takes place. Although it is prevented that too thin a yarn is spun just prior to using up the running fiber band, too large a fiber amount is introduced when connecting the end of the new fiber band. This results in at first a thicker yarn being spun prior to entirely using up the old fiber band following the automatic start spinning process.
It is also known, as disclosed in German application DE-OS No. 25 21 851, to fill up all the containers with the same lengths of fiber bands and to provide a measuring device which measures the introduced length of the fiber band and determines the time period for connecting a new fiber band. A separating device is thereby provided immediately in front of the feeding device by means of which the old fiber band is cut off whereby the same is subsequently still introduced into the spinning device in its entirety. Presumably this results in a thickening portion at the yarn end which is easily detected on the spool during the subsequent start spinning process. The joining of the end of the new fiber band occurs by a direct, manual introduction into the spinning device.
Furthermore, it is known, as disclosed in JP-OS No. 59-76 932, to indirectly determine the respective contents of a container stocked with the fiber band whereby the respective filling level is determined by counting the rotation of the yarn withdrawal rollers or the take-up spool. The idle times during yarn breaks and spool exchanges are deducted. From these values conclusions can be drawn as to the respective content of the fiber band containers so that a signal is given for changing a container as needed.
It is also known according to German DE-OS No. 25 54 915 to watch the content of the containers directly, for example by measuring the running length of the fiber band at the delivery device, or by measuring the weight decrease of the container, or by measuring the filling height. As a lower limiting value is reached, a signal is given that allows one to exchange the almost empty fiber band containers in good time prior to the start of a longer, maintenance free period, as for example prior to a weekend.
An object of the present invention is to provide a process of the above-mentioned kind that enables a fully automatic joining of a new fiber band whereby at the same time it is guaranteed that no faulty portions exist in the spun yarn due to the joining of the new fiber band.
In a first embodiment of the present invention it is provided that the feeding device is brought to a still stand prior to the entry of the end of the fiber band into the spinning device. Thereupon the fiber band protruding from the spinning device and/or the end of the new fiber band are treated in such a manner and connected to each other that the connecting point results in at least a similar if not substantially the same yarn number as the other areas of the fiber band.
This arrangement makes it possible to obtain a constant yarn number in the fiber band following a connecting of the new fiber band so that correspondingly the spun yarn is also constant. In a preferred development of the invention it is provided that the end of the fiber band made available is spliced with the end of the fiber band protruding from the spinning device.
In another embodiment it is provided that the feeding device of the spinning device is brought to a standstill prior to the entry of the end of the fiber band into the spinning device, thereby allowing the end of the new fiber band to be connected to the end of the fiber band protruding from the spinning device. Subsequently to the joining of the ends of the old and new fiber bands, the feeding device of the spinning device is switched on only as long as the joining position is running into the spinning device. The fibers introduced during this time period are transported off by the spinning device whereupon the automatic start spinning process is activated. With this arrangement, the quality of the joining position between the end of the new fiber band and the end of the old fiber band does not matter since the fibers existing in the area of this joining point are not spun into the yarn but transported off as waste material. There is also provided a pneumatic splicing or twisting with this kind of fiber band connection. However, since in this case the joining position has no influence upon the yarn quality, less elaborately designed connections may also be provided. For example, a simple rubbing together of the end of the new fiber band with the end of the old fiber band.
Both of the embodiments exhibit the advantage that the old fiber band is not spun to its very end prior to attaching and introducing a new fiber band. Consequently, the end of the old fiber band has no influence upon the spun yarn quality. Since a sufficiently long piece of the old fiber band still protrudes out of the spinning device at the time of joining the new fiber band, the joining process can be fully automated with relatively simple means.
In order to proceed with the stopping of the feeding device of a spinning device in good time prior to running through the end of the fiber band in the spinning device, a further development of the invention provides that a sufficiently long piece of fiber band remains in the containers and that the spinning device includes a measuring device for determining the run-in length of the fiber band. This device is coupled with a device for bringing the feeding device of the spinning device to a standstill. For the same purpose there is provided in another development of the invention that the fiber bands deposited in the containers are provided with a marking at a distance from their ends, and that the spinning device is provided with a device for recognizing the marking and activating a device for bringing the feeding device to a standstill. This kind of marking, whether it is of a chemical, optical, or mechanical nature, does not require the deposit of an exactly measured length of fiber band in the containers.
In a further development of the invention for executing the process at a spinning machine with a plurality of open-end spinning devices, which each contain a feeding device for drawing in a respective fiber band presented out of a container, it is provided, that each spinning device is equipped with a device switching off the fiber feeding device for measuring the length of the fiber band run-in to the spinning device. Furthermore there is provided a movable maintenance apparatus assigned to respectively one spinning device which is equipped with devices for picking up and connecting the fiber band protruding from the spinning device with the end of a new fiber band.
Especially since the old fiber band protrudes out of the spinning device with a substantially long piece while the feeding device has already been switched off, the joining with the end of a new fiber band is done fully automatically in a very simple manner.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.